1. Field of the Invention
The present invention relates to an endoscope main body constituting an endoscope in a state in which an elongated detachable observation optical system is attached to the endoscope main body, and the endoscope.
2. Description of the Related Art
As disclosed in, e.g., JP-A 2000-33071 (KOKAI), insertion sections of a plurality of endoscopes are introduced into a body cavity through one over-tube to perform a procedure while observing a surgical instrument which projects from a distal end of the insertion section of the first endoscope and a surgical instrument which projects from a distal end of the insertion section of the second endoscope by using, for example, the first endoscope.
On the other hand, it is known that instead of using the plurality of endoscopes, for example, two bendable arm sections are disposed on the distal end of the insertion section of one endoscope. To bend these arm sections, two or four wires are attached to each of the arm sections, and further to bend bending portions provided on proximal ends of the arm sections, for example, two or four wires are attached thereto. Moreover, in the insertion section of the endoscope, there is disposed a channel tube which permits the surgical instrument to project from the proximal end side of the insertion section through the distal end of each arm section. Therefore, in this endoscope, the surgical instrument is led through each channel tube, whereby the distal end of the surgical instrument projects from the distal end of the arm section while arbitrarily bending the arm section, which enables the procedure disclosed in JP-A 2000-33071 (KOKAI) with one endoscope.